1. Technical Field
The present disclosure relates to an ejector and a heat pump apparatus including the ejector.
2. Description of the Related Art
Ejectors are used as decompression means of various apparatuses, such as vacuum pumps and refrigeration cycle apparatuses. As illustrated in FIG. 10, a refrigeration cycle apparatus 200 described in Japanese Patent No. 3158656 includes a compressor 102, a condenser 103, an ejector 104, a separator 105, and an evaporator 106. The ejector 104 receives a refrigerant liquid as a drive flow from the condenser 103, sucks in and pressurizes a refrigerant vapor supplied from the evaporator 106, and ejects the refrigerant liquid and the refrigerant vapor toward the separator 105. The separator 105 separates the refrigerant liquid and the refrigerant vapor from each other. The compressor 102 sucks in the refrigerant vapor pressurized by the ejector 104. Thus, the compression work to be done by the compressor 102 is reduced and the COP (coefficient of performance) of a refrigeration cycle is improved.
As illustrated in FIG. 11, the ejector 104 includes a nozzle 140, a suction port 141, a mixer 142, and a pressurizer 143. A plurality of connection ports 144, through which the inside of the nozzle 140 is connected to the outside of the nozzle 140, are disposed near the outlet of the nozzle 140. The refrigerant vapor is sucked into the ejector 104 through the suction ports 141. A part of the refrigerant vapor sucked into the ejector 104 flows to the inside of the nozzle 140 through the connection ports 144.
The nozzle 140 of the ejector 104 has a tapering section near the outlet thereof. In the tapering section, the flow velocity of the refrigerant increases and the pressure of the refrigerant decreases. Accordingly, the phase of the refrigerant (drive flow), which is supplied to the nozzle 140, changes from a liquid phase to a gas-liquid two-phase in the tapering section. In other words, the ejector 104 illustrated in FIG. 11 is called a “two-phase flow ejector”.